/**
 * Copyright © 2018, LeonKeh
 * <p>
 * All Rights Reserved.
 */

import java.util.ArrayList;

/**
 * 类功能描述
 *
 * @author Leon
 * @version 2018/12/19 15:06
 */
public class AVLTree<K extends Comparable<K>, V> {

    private Node root;
    private int size;

    public AVLTree() {
        root = null;
        size = 0;
    }

    public int getSize(){
        return size;
    }

    public boolean isEmpty(){
        return size == 0;
    }

    private int getHeight(Node node) {
        if (null == node) {
            return 0;
        }
        return node.height;
    }

    private int getBalanceFactor(Node node) {
        if (null == node) {
            return 0;
        }
        return getHeight(node.left) - getHeight(node.right);
    }

    public void add(K key, V value){
        root = add(root, key, value);
    }

    private Node add(Node node, K key, V value){
        if (null == node) {
            size++;
            return new Node(key, value);
        }

        if (key.compareTo(node.key) < 0) {
            node.left = add(node.left, key, value);
        } else if (key.compareTo(node.key) > 0) {
            node.right = add(node.right, key, value);
        } else { // key.compareTo(node.key) == 0
            node.value = value;
        }

        // Calculate the height
        node.height = 1 + Math.max(getHeight(node.left), getHeight(node.right));

        // Calculate the factor of balance for current node
        int balanceFactor = getBalanceFactor(node);
        if (Math.abs(balanceFactor) > 1) {
            System.out.println("unbalance：" + balanceFactor);
        }

        return node;
    }

    private Node getNode(Node node, K key){

        if (null == node) {
            return null;
        }

        if (key.equals(node.key)) {
            return node;
        } else if (key.compareTo(node.key) < 0) {
            return getNode(node.left, key);
        } else {  // if(key.compareTo(node.key) > 0)
            return getNode(node.right, key);
        }
    }

    public boolean contains(K key) {
        return getNode(root, key) != null;
    }

    public V get(K key){

        Node node = getNode(root, key);
        return null == node ? null : node.value;
    }

    public void set(K key, V newValue) {
        Node node = getNode(root, key);
        if (node == null) {
            throw new IllegalArgumentException(key + " doesn't exist!");
        }
        node.value = newValue;
    }

    private Node minimum(Node node) {
        if (node.left == null) {
            return node;
        }
        return minimum(node.left);
    }

    // 删除掉以node为根的二分搜索树中的最小节点
    // 返回删除节点后新的二分搜索树的根
    private Node removeMin(Node node){

        if (node.left == null) {
            Node rightNode = node.right;
            node.right = null;
            size --;
            return rightNode;
        }

        node.left = removeMin(node.left);
        return node;
    }

    // 从二分搜索树中删除键为key的节点
    public V remove(K key){

        Node node = getNode(root, key);
        if(null != node){
            root = remove(root, key);
            return node.value;
        }
        return null;
    }

    private Node remove(Node node, K key){

        if( node == null ) {
            return null;
        }

        if( key.compareTo(node.key) < 0 ) {
            node.left = remove(node.left , key);
            return node;
        } else if (key.compareTo(node.key) > 0 ) {
            node.right = remove(node.right, key);
            return node;
        } else { // key.compareTo(node.key) == 0

            // 待删除节点左子树为空的情况
            if(node.left == null){
                Node rightNode = node.right;
                node.right = null;
                size --;
                return rightNode;
            }

            // 待删除节点右子树为空的情况
            if(node.right == null){
                Node leftNode = node.left;
                node.left = null;
                size --;
                return leftNode;
            }

            Node successor = minimum(node.right);
            successor.right = removeMin(node.right);
            successor.left = node.left;

            node.left = node.right = null;

            return successor;
        }
    }

    private class Node {
        public K key;
        public V value;
        public Node left,right;
        public int height;

        public Node (K key, V value) {
            this.key = key;
            this.value = value;
            this.left = null;
            this.right = null;
            this.height = 1;
        }
    }

    public static void main(String[] args) {
        System.out.println("Pride and Prejudice");

        ArrayList<String> words = new ArrayList<>();
        if(FileOperation.readFile("d:\\todo\\pride-and-prejudice.txt", words)) {
            System.out.println("Total words: " + words.size());

            AVLTree<String, Integer> map = new AVLTree<>();
            for (String word : words) {
                if (map.contains(word))
                    map.set(word, map.get(word) + 1);
                else
                    map.add(word, 1);
            }

            System.out.println("Total different words: " + map.getSize());
            System.out.println("Frequency of PRIDE: " + map.get("pride"));
            System.out.println("Frequency of PREJUDICE: " + map.get("prejudice"));
        }

        System.out.println();
    }
}
